mxz 440 "CLUNK!" when on the gas - Snowmobile Forum: Your #1 Snowmobile Forum

brandcole73 · 01-17-2008, 03:52 PM

My sled is making a clunk when I slow down then accelerate. At first I thought it was coming from the brake rotor, its a little sloppy on the shaft. I had a mechanic look it over and he could not find out where it was coming from. I noticed today that the secondary slides about an 1/8 inch in and out. That seems to be the sound I am hearing. I have been told to check the chain tension, but I'm sure the sound is that wheel sliding in and out. My buddy checked the chain when he looked it over and it was all right then. (last year) Any ideas?

jKsled · 01-17-2008, 04:09 PM

i am having similiar problem. it's coming from the chaincase, and it will clunk when accelerating. if you can feel it "skip" when it clunks, it's likely the chain is slipping in your chaincase. i don't know if it's not tight enough or the gears are stripped, but start by tightening as much as possible but only with your fingers. if it still does it, maybe the chaincase components need replacing; you'll have to look at it and see.

brandcole73 · 01-17-2008, 04:15 PM

How do I tighten the chain? Is the tension adjuster the bolt coming out behind the clutch? I don't think I feel any skipping but it can't hurt to check this.

**smallengineguy** · 01-17-2008, 09:19 PM

The secondary should slide a little each way, to keep the belt aligned. The chain tensioner is on the top of the chaincase, toward the back. It should have a pin through it.

brandcole73 · 01-19-2008, 04:53 PM

A friend and I looked it over today. He thinks the secondary has too much slop side to side. There is a plastic spacer on the outside of it. Could this have been geting worn thin, allowing the excess play? It's only 1/8" or less thick now. He had a similer noise on one of his and replaced this spacer to fix it.

jimmyv13 · 01-21-2008, 09:32 AM

I have an MXZ 440 and my secondary moves that much if not more. Sounds like something in the chaincase...

brandcole73 · 01-22-2008, 02:42 PM

I tightened the chain tension today. Got it finger tight and backed off till the hole lined up, about 1/4 turn or a little less. It is still making that clunk. I'm sure it's coming from the clutch side. It sounds like that secondary slamming side to side. It happens when I let off and then gas on before the sled stops. It doesn't make that noise when I start from a dead stop. Any ideas? I had a mechanis look the clutches over last year when it started making this noise and he couldn't see anything wrong there.

**RJ Gleason** · 01-22-2008, 02:43 PM

Check the drive shaft for the track.
Possible bearing failure.

brandcole73 · 01-22-2008, 04:04 PM

will do thanks.

brandcole73 · 01-26-2008, 11:43 AM

I put a new spacer (bushing) in the secondary, brtween the bolt and clutch wheel. It was metal, not plastic like I thought. But that wasn't it. How do I check the drive shaft bearings? Maybe it is the brake rotor. It is loose, the key must be getting worn?

**RJ Gleason** · 01-27-2008, 04:33 AM

Raise up the rear of the sled so the track is off the floor/ground and loosen the tensioners all the way so that you have lots of slack.
Then you can reach up under there and see if there is any play up an down in the drive shaft.
If there is, you need to replace the bearings immediately.

brandcole73 · 02-01-2008, 07:19 PM

RJ, you were right. I checked the drive shaft and found it wobbled in the bearing. Thanks for the advice!!!

IndianRvrShiver · 02-01-2008, 07:31 PM

HOORAY for RJ!!!!

He d'man!!!

**RJ Gleason** · 02-02-2008, 06:44 AM

*** Bowing******
No applause, just throw money!!